Means for regulating the temperature of electrical heating and cooking apparatus.



I J. G. P. KIRKWOOD. HEARS FOB BEGULATING THE TEMPERATURE OF ELECTRICAL HEATING AND COOKING APPARATUS.

APPLICATION FILED HAB- 8, 1912.

1,025,576. Patented May 7, 1912.

15 1.6 Pa r m (rm amPm/rmewmz.

exact description of the same.

UNITED STATES PATENT OFFICE.

JAMES CHARLES PARKE KIRKWOOD, OF WELLINGTON, NEW ZEALAND, A SS-IGNOR TO HERBERT DOUGLAS VICKERY, OF WELLINGTON, NEW ZEALAND. Y

MEANS FOR BEGULATING THE. TEMPEEATERE OF ELECTRICAL HEATING AND COOK- ING APPARATUS.

Be it known that I, JAMES C rtis's PARKE Krnxwoon, subject of the King of Great Britain and Ireland,, residing at 88 Willis street, in the city of Wellington, in the Dominion of New Zealand, electrical engineer, have invented anew anduseful Improvement in Means for Re latingthe Temperature of Electrical eatin and Cooking Apparatus; and I do here ,y declare the followingto be a full, clear, and

ThlS invention provides for the automatic regulation of the temperature of electric heating and cooking apparatus suchas electr1c stoves and ovens, electrlc llOIlS, urns,

and all such like apparatus where the heating medium is electricity.

he desired regulation is obtained by means whereby the heating circuit is automaticallycut out, when a particular part of the apparatus reaches a desired temperature and when the temperature of theisa-id particular part decreases sufficiently, the circuit will be automatically renewed The means provided allow of the degree of heat ator near which theapparatusis desired to be retained, to be simply and easily regulated or changed by an operator.

The expanslve and contractive properties due to heating and cooling. of suitable metals or materials are utilized to effect the automatic breaking and making or an electrical circuitwhich contains the heating element. The expanding or contracting metal being eithera art of the heating apparatus or a specia part attached thereto, the expansion and contraction of said metal is caused by the increase and decrease of the temperature of the apparatus itself.

Reference is to be had to the accompanying drawings forming a part of this specification, in which similar. characters of referenoe indicate corresponding parts. inall the figures.

i I I a Figure 1, 1s a sectional elevation of an' electric water heater in which my invention is embodied. Fig. 2," is a diagrammatic view showing the electrical circuits, Fig. 3, isa sectional elevationof the invention applied to a laundry iron. Fig 4, is a plan v ew of a regulating indicator.

Referrin to Figs. 1 and 2 the numeral 1 indicates t e vessel of an electrical water Specification of Letters Patent. Application flled ltarc h 8, 1912. Serial No. 682,425. v

at one end thereof. On-the other end of.

Patented-May 7, 1912.

.the member 3, which end projects through the wall of the vessel 1, is pivoted alever.

5, the end thereof being pivoted in the end of the marble slab 4 as shown. The long arm of the lever 5 is provide'd with a contact piece '2' insulated from the lever and adapted to make contact with another contact piece 8 fixed to, but insulated .from' a spring arm 9. A screw 10 passing through the upper end of the bracket 6 is used to adjust the relation of the contact 8 to the contact -7. Ajsolenoidfl i is located in a suitable position the drawing shows it mounted upon the distribution board of electric supply. The solenoid has a lever 15 pivoted atone end to its core 16. The lever 15 is pivoted in astud 17 andit-s long arm is provided with. a contactpiece '18 fixed to but insulated from the lever 15. A contact piece 19 is provided below the contact piece 18 the two cont-act pieces being normally held together by means of a sprin 20 attached to the lever 15; A Wire 21 see particularly Fig. .2) leads from the contact .piece 19 to the heating element or resistance 22, to the other end of which one of the leading wires 23 is connected, the other.

leading wire 24 being connected to the con-- tactpiece 18 so ,that when the contact'pieces are normally held together by. the spring I 20 'as shown in Fig.1 current flows through the resistance 22 and heats the contents of the vessel.

The means by which current is auto matically out out when the, apparatus reaches a desired heat will nowbe described: A,wire 25 leads from the leadin wire 24 to one end of the solenoid 14 while-a wire 26 leads from the other end of said solenoid to .the contactpiece7 on the lever 5. Another wire 27 leads from the leading wire 23 to the contact piece 8 on the front end .of the arm- 9. It will be seen that while a the contact pieces 1 8,and 19 are together current will continue to flow, through the resistance 22 but when :the vessel becomes sufiiciently heated to expand the bottom 2 and member 3 and thereby operate the lever 5 to bring the contacts 7 and 8 together, part of the current will be shunted through 5 the solenoid 11 which immediately becoming an electro-magnet will pull the core 16 downward and so break the contact of the contact pieces 18 and 19 thereby cutting off the whole of the current from the resistance 22. Thus the solenoid and its accompanying'parts form an electromagnetic switch. Immediately the vessel cools sufiiciently to allow the bottom 2 and member 3 to contract and to part the contact pieces 7 and 8, the solenoid will cease to be an electromagnet thereby allowing the lever 15 to be returned to its normal position by means of the spring 20, and bring the contact pieces 18 and 19 together thus closing the circuit 20 through the heating resistance.

Fig.3 represents the device as applied to an electric'fla't iron, and in order that the construction may be easily followed the same reference numerals are used to indi- 5 cate the same parts. In this case the bottom 28 of the iron is used as the expansion medium in a similar manner to the bottom 2 of the water heater. The lever 5 is pivoted in a bracket'29 mounted on an asbestos 30 slate plate 30 or other similar non-metallic substance of which the co-eflicient of expansion is low, the front end of said plate being fixed by a screw 39 or other suitable means near the point of the iron to a metal plate 41 5 disposed directly above the resistance element. The rear end 32 of the lever 5 is pivoted in a bracket 33, fixed to therear end of the'bottom 28, which when it expands will cause the contact pieces 7 and 8 to be 40 brought together and the current cut oil from the resistance element in the same manner as described u reference to the apparatus shown in Fig. 1. The solenoid 14, stud 17 and contact plece 19 are all mounted on the asbestos slate plate 30 in place of being mounted upon the distribution board as in that of Fig. 1, while the space 40 between plate 41 and bottom 28 is designed to receive the resistance element.

The pointof temperature at which the current is cut off is determined by the distance of the contact pieces 7 and 8 and such distance maybe adjustedby means of the adjusting screw "10. To furnish an indication to the operator of the temperature to which the apparatus is to be set, the adjusting screw 10 is provided with a pointer 3 1 (seeFig. 4) thepoint 35 being adapted to snip into recesses 36 on an indicator or dial 37 which may be vmarked off to show at what temperature the current will be cut off.

It is to be observed that in both constructions shown, it-is one of the normal walls of the container, (which term is applicable generically to both the vessel 1 and the iron),

wherein said element is included, a shunt which contracts and expands through the action of the resistance element and, by means of its connections with the solenoid, serves to operate the latter. In the first construction the part 3 is directly connected to lever 5 and actuates the same, but since this part is connected to the bottom 2, it is the expansion and contraction of the latter which may be considered as effecting the thermostatic action of the aforesaid part 3. In the iron construction, also, it is the bottom 28 which is directly affected by the resistance element and acts as a thermostat to control the solenoid. As further regards the iron construction, it is to be noted that all working parts of the apparatus are contained therewithin, which is a matter of great convenience, as will be understood, and that the inclusion of a solenoid in the apparatus 'is'also a matter of great advantage since it provides for a gradual make and break of the main circuit and thus prevents sparking and consequent rapid, burning out of the iron. Finally it is to be noted that the indicator is located upon the body of the flat iron, so that' the temperature at 'which'the main circuit is to be closed and the current to be cut off can be readily determined, and the said indicator can be readily manipulated to control the temperature when desired.

What I claim as my invention and desire to secure by Letters Patent of the United States, is

1. The combination, with a container having one of its normal walls free to expand and contract, of a resistance element disposed within said container adjacent said wall for heating the same; a main circuit I05 circuit having an electro-magnetic switch included therein, and electrically-operated connections for automatically operating the switch consequentupon the expansion and. contraction of said wall, to alternately mak one of said circuits and break the other.

2. The combination, with a container having one of its normal walls free to expand and contract, of a resistance element disposed within said container adjacent said wall for heating the same, a main circuit wherein. said element is included, a shunt circuit having a solenoid included therein, and electrically-operated connections for automatically operating the solenoid consequent upon 2 the expansion and contraction of said wall, to alternately make one of said circuits and break the other. I

3. The combination, with a hollow fiat iron having its bottom wallfree to expand and contract, of a resistance element and an electro-magnetic switch disposed within the interior of said flat iron, said element being located adjacent said wall to heat the same, a main circuit wherein said element is included, a shunt circuit ,wherein said switch is included, and electrically operated connections for automatically operating the i switch conse uent upon the expansion an contraction 0 said wall, to alternately make one of said circuits and break the other.

i 4. The combination, with a hollow flat iron having its bottom wall free to expand and contract, of a resistance element and a solenoid disposed within the interior of said fiat iron, said element being located adjacent said wall to heatthe'same, a main circuit wherein said element is included, a shunt circuit wherein said, solenoid is included, and electrically operated connections for automatically operating the solenoid consequent upon the expansion and-contraction of said wall to alternately make one of said circuits and break the other.

5. The combination, with a hollow flat iron, of a resistance heating element and a solenoid disposed within the interiorof said flat iron, a main circuit wherein said element is included, a shunt circuit wherein said solenoid is included, and electricallyoperated means for automat-icallyoperatin the solenoid to make the shunt circuit an break the main circuit when the temperature of the heated flat iron rises, above a predetermined point, and to break the shunt circuit and make themain circuit whenthe temperature "subsequently falls below such point.

6. The combination, with a container hav-.

ing one of its normal walls free to expand and contract, of a resistance element disposed within said container adjacent said wall for heating the same, a mam circuit wherein said element is included, a shunt v circuit having an electro-magnetic switch included therein, electrically-operated connections for automatically operating the switch consequent upon the expansion and contraction' of said wall, to alternately make one of said circuits and break the other, and a controller associated with said electrical connections for regulating the de 'ee of heat at which the main circu1t is ma e and broken.

7. The combination, with a hollow flat iron having its bottom wall free to expand and contract, of a resistance element and an 'electro-magnetic switch disposed within the interior of said flat iron, said element being located adjacent said wall to heat the same, a main circuit wherein said element, is included, a shunt circuit wherein said switch is included, electrically operated connections for-automatically operating the switch consequent upon the expansion and contraction of said wall, to alternately make one of said circuits and break the other, and a controller secured to one of the other walls of said flat iron and associated with said electrical connections for regulating the degree of heat at which main circuit is made and broken.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing Witnesses.

JAMES CHARLES PARKE KIRKWOOD.

Witnesses:

SYDNEY HAMLET HIGGS, 'EnMom) PATRIOKODONNELL. 

